Hello all! I hope that you are all out there having fun tweaking ASM Security policies, revamping your Web Acceleration profiles and having fun with the latest version of TMOS! I myself am looking forward to kicking the tires on TMOS version 11.3 very soon…

I have a new item to present to you today, though it isn’t BIG-IP related sadly enough. At least it IS a network tweak! To be more precise, it’s a networking related performance tweak for Microsoft’s DirectAccess 2010 that once implemented could help you increase your servers performance by up to 25%!

Did I mention that it is also fast and relatively painless to pull off?

Normally on a DirectAccess 2o10 server the first CPU core processes the majority (if not all) the connections coming into and out of the server. This is crazy in today’s world of multi-core multi-CPU servers. Turning on Receive Side Scaling allows you to spread that load more evenly across all of your compute cores and is an absolute no-brainer if you have a server that can handle it.

All that you have to do is go into the properties of your Intel NIC, turn on Receive Side Scaling and configure the number of queues. Receive Side Scaling is {plagiarized} “a technology that allows you to process a TCP connection across multiple cores. This allows for more efficient cache and processor usage when your TCP connection is not tied to a single core. When you are using this feature it will only use real physical cores to process TCP connections. Note however, you are not able to use this with hyper thread cores.”

Now that you know what Receive Side Scaling is, you will find that Receive Side Scaling Queues act as a buffer space that is used between the NIC and the CPU when you are using Receive Side Scaling. When you turn this setting on you need to realize that there is a trade off between host CPU and performance. The more queues that you add the more load it will create across all the CPU cores.

You will definitely want to schedule a maintenance window to apply these changes as it does cause the servers to drop connections for a minute after you make the changes on the interface.